medwireNews: The presence of subsyndromal affective symptoms is associated with a significantly shorter time to relapse among euthymic patients with bipolar disorder (BD), Spanish research shows.
In a study of 225 BD outpatients who were clinically euthymic (without DSM IV-TR criteria for affective episodes) at baseline, median time to relapse was more than two-thirds shorter for those with subsyndromal symptoms at baseline compared with asymptomatic individuals.
"Our work confirms the important role of subsyndromal symptoms as a risk factor for affective relapse in BD patients," comment Consuelo de Dios (University Hospital La Paz, Madrid) and team.
Of the patients, 163 (72.4%) were asymptomatic at baseline, with Hamilton Depression Rating scale (HDRS) and Young Mania Rating scale (YMRS) scores of less than 8, and 62 (27.6%) had subsyndromal symptoms, with HDRS and/or YMRS scores of 8-14.
Over a median follow-up period of 157.6 weeks, 57.3% of the patients experienced at least one affective episode, including depressive (19.2%), manic (5.4%), hypomanic (22.8%), and mixed episodes (10.3%).
The researchers found that median survival time to relapse was 109 weeks in patients who were asymptomatic at baseline compared with 35 weeks in those with subsyndromal symptoms - a significant difference.
The team also found that the presence of psychosocial stress was an independent risk factor for reduced time to relapse among the participants, at a hazard ratio of 2.2.
There were no significant associations between time to relapse and other socio-demographic or clinical variables, including BD subtype, predominant polarity or illness duration, they note.
Writing in the Journal of Affective Disorders, de Dios et al conclude: "Our results show that in a Spanish non-tertiary BD cohort, subsyndromal BD symptoms and psychosocial stress at baseline predict earlier affective episode relapse."
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